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Romain Monclus - One of the best experts on this subject based on the ideXlab platform.
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xylem anatomy correlates with gas exchange water use efficiency and growth performance under contrasting water regimes evidence from Populus deltoides Populus nigra hybrids
Tree Physiology, 2009Co-Authors: Romain Monclus, Franck Brignolas, Regis Fichot, Francoise Laurans, Alain Moreau, Gilles PilateAbstract:Six Populus deltoides Bartr. ex Marsh. x P. nigra L. genotypes were selected to investigate whether stem xylem anatomy correlated with gas exchange rates, water-use efficiency (WUE) and growth performance. Clonal copies of the genotypes were grown in a two-plot common garden test under contrasting water regimes, with one plot maintained irrigated and the other one subjected to moderate summer water deficit. The six genotypes displayed a large range of xylem anatomy, mean vessel and fibre diameter varying from about 40 to 60 microm and from 7.5 to 10.5 microm, respectively. Decreased water availability resulted in a reduced cell size and an important rise in vessel density, but the extent of xylem plasticity was both genotype and trait dependent. Vessel diameter and theoretical xylem-specific hydraulic conductivity correlated positively with stomatal conductance, carbon isotope discrimination and growth performance-related traits and negatively with intrinsic WUE, especially under water deficit conditions. Vessel diameter and vessel density measured under water deficit conditions correlated with the relative losses in biomass production in response to water deprivation; this resulted from the fact that a more plastic xylem structure was generally accompanied by a larger loss in biomass production.
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impact of drought on productivity and water use efficiency in 29 genotypes of Populus deltoides Populus nigra
New Phytologist, 2006Co-Authors: Romain Monclus, Erwin Dreyer, Marc Villar, Didier Delay, Jeanmichel Petit, Cecile Barbaroux, Didier Le Thiec, Francis M Delmotte, Claude BrechetAbstract:We examined the relationships among productivity, water use efficiency (WUE) and drought tolerance in 29 genotypes of Populus x euramericana (Populus deltoides x Populus nigra), and investigated whether some leaf traits could be used as predictors for productivity, WUE and drought tolerance. At Orleans, France, drought was induced on one field plot by withholding water, while a second plot remained irrigated and was used as a control. Recorded variables included stem traits (e.g. biomass) and leaf structural (e.g. leaf area) and functional traits [e.g. intrinsic water use efficiency (Wi) and carbon isotope discrimination (Delta)]. Productivity and Delta displayed large genotypic variability and were not correlated. Delta scaled negatively with Wi and positively with stomatal conductance under moderate drought, suggesting that the diversity for Delta was mainly driven by stomatal conductance. Most of the productive genotypes displayed a low level of drought tolerance (i.e. a large reduction of biomass), while the less productive genotypes presented a large range of drought tolerance. The ability to increase WUE in response to water deficit was necessary but not sufficient to explain the genotypic diversity of drought tolerance.
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impact of drought on productivity and water use efficiency in 29 genotypes of Populus deltoides Populus nigra
New Phytologist, 2006Co-Authors: Romain Monclus, Erwin Dreyer, Francis Delmotte, Marc Villar, Didier Delay, Jeanmichel Petit, Cecile Barbaroux, Didier Le Thiec, Claude BrechetAbstract:Summary • We examined the relationships among productivity, water use efficiency (WUE) and drought tolerance in 29 genotypes of Populus × euramericana (Populus deltoides×Populus nigra), and investigated whether some leaf traits could be used as predictors for productivity, WUE and drought tolerance. • At Orleans, France, drought was induced on one field plot by withholding water, while a second plot remained irrigated and was used as a control. Recorded variables included stem traits (e.g. biomass) and leaf structural (e.g. leaf area) and functional traits [e.g. intrinsic water use efficiency (Wi) and carbon isotope discrimination (Δ)]. • Productivity and Δ displayed large genotypic variability and were not correlated. Δ scaled negatively with Wi and positively with stomatal conductance under moderate drought, suggesting that the diversity for Δ was mainly driven by stomatal conductance. • Most of the productive genotypes displayed a low level of drought tolerance (i.e. a large reduction of biomass), while the less productive genotypes presented a large range of drought tolerance. The ability to increase WUE in response to water deficit was necessary but not sufficient to explain the genotypic diversity of drought tolerance.
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productivity leaf traits and carbon isotope discrimination in 29 Populus deltoides p nigra clones
New Phytologist, 2005Co-Authors: Romain Monclus, Erwin Dreyer, Francis Delmotte, Marc Villar, Didier Delay, Eric Boudouresque, Jeanmichel Petit, Nicolas MarronAbstract:Summary • Here we tested whether some leaf traits could be used as predictors for productivity in a range of Populus deltoides × P. nigra clones. These traits were assessed in 3-yr-old rooted cuttings from 29 clones growing in an open field trial, in a five randomized complete block design, under optimal irrigation. •Variables were assigned to four groups describing productivity (above-ground biomass, total leaf area), leaf growth (total number of leaves increment rate), leaf structure (area of the largest leaf, specific leaf area, carbon and nitrogen contents), and carbon isotope discrimination in the leaves (Δ). • High-yielding clones displayed larger total leaf area and individual leaf area, while no correlation could be detected between productivity and either leaf structure or Δ. By contrast, Δ was negatively correlated with number of leaves increment rate and leaf N content. •Our study shows that there is a potential to improve water-use efficiency in poplar without necessarily reducing the overall productivity.
Nicolas Marron - One of the best experts on this subject based on the ideXlab platform.
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genetic variation of leaf traits related to productivity in a Populus deltoides Populus nigra family
Canadian Journal of Forest Research, 2006Co-Authors: Nicolas Marron, R CeulemansAbstract:In breeding and selection, two of the main goals of hybridization are to combine favourable traits from different species and to obtain high hybrid vigor (or heterosis). The objectives of our study were (1) to determine which leaf traits are most closely linked to growth in a cross between Populus deltoides Bartr. ex Marsh. and Populus nigra L. and (2) to estimate the relevance of this cross for selection of highly productive genotypes. To achieve these objectives, 26 poplar F1 hybrids and their parents were studied during their second growing season in central France. Tree growth (i.e., growth rates of stem height, circumference, and volume) was monitored during 1 month, and leaf traits (i.e., increases in number of leaves, maximum individual leaf area, specific leaf area, petiole length, and dry mass, leaf carbon and nitrogen contents, and internode length) were estimated at the end of the 1-month period. Growth traits were tightly correlated to most of the leaf traits. More precisely, it appeared that ...
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productivity leaf traits and carbon isotope discrimination in 29 Populus deltoides p nigra clones
New Phytologist, 2005Co-Authors: Romain Monclus, Erwin Dreyer, Francis Delmotte, Marc Villar, Didier Delay, Eric Boudouresque, Jeanmichel Petit, Nicolas MarronAbstract:Summary • Here we tested whether some leaf traits could be used as predictors for productivity in a range of Populus deltoides × P. nigra clones. These traits were assessed in 3-yr-old rooted cuttings from 29 clones growing in an open field trial, in a five randomized complete block design, under optimal irrigation. •Variables were assigned to four groups describing productivity (above-ground biomass, total leaf area), leaf growth (total number of leaves increment rate), leaf structure (area of the largest leaf, specific leaf area, carbon and nitrogen contents), and carbon isotope discrimination in the leaves (Δ). • High-yielding clones displayed larger total leaf area and individual leaf area, while no correlation could be detected between productivity and either leaf structure or Δ. By contrast, Δ was negatively correlated with number of leaves increment rate and leaf N content. •Our study shows that there is a potential to improve water-use efficiency in poplar without necessarily reducing the overall productivity.
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diversity of leaf traits related to productivity in 31 Populus deltoides x Populus nigra clones
Tree Physiology, 2005Co-Authors: Nicolas Marron, Erwin Dreyer, Francis Delmotte, Marc Villar, Didier Delay, Eric Boudouresque, Jeanmichel Petit, Jeanmarc Guehl, Franck BrignolasAbstract:To test if some leaf parameters are predictors of productivity in a range of Populus deltoides (Bartr.) Marsh. x P. nigra L. clones, we assessed leaf traits and productivity in 2-month-old rooted cuttings from 31 clones growing in 4-l pots in a greenhouse, under conditions of controlled temperature and optimal irrigation. We evaluated four groups of variables describing (1) productivity (total biomass), (2) leaf growth (total leaf number increment and total leaf area increment rate), (3) leaf structure (specific leaf area and nitrogen and carbon contents) and (4) carbon isotope discrimination (delta), which is negatively correlated with time-integrated water-use efficiency. High-yielding clones did not necessarily display high leaf growth rates, but they displayed a larger total leaf area, lower specific leaf area and lower leaf nitrogen concentration than clones with low productivity. Total leaf area was mainly controlled by maximal individual leaf area and total leaf area increment rate (r = 0.51 and 0.56, respectively). Carbon isotope discrimination did not correlate with total biomass, but it was associated with total number of leaves and total leaf area increment rate (r = 0.39 and 0.45, respectively). Therefore, leaf area and specific leaf area were better indicators of productivity than leaf growth traits. The observed independence of delta from biomass production provides opportunities for selecting poplar clones combining high productivity and high water-use efficiency.
Franck Brignolas - One of the best experts on this subject based on the ideXlab platform.
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xylem anatomy correlates with gas exchange water use efficiency and growth performance under contrasting water regimes evidence from Populus deltoides Populus nigra hybrids
Tree Physiology, 2009Co-Authors: Romain Monclus, Franck Brignolas, Regis Fichot, Francoise Laurans, Alain Moreau, Gilles PilateAbstract:Six Populus deltoides Bartr. ex Marsh. x P. nigra L. genotypes were selected to investigate whether stem xylem anatomy correlated with gas exchange rates, water-use efficiency (WUE) and growth performance. Clonal copies of the genotypes were grown in a two-plot common garden test under contrasting water regimes, with one plot maintained irrigated and the other one subjected to moderate summer water deficit. The six genotypes displayed a large range of xylem anatomy, mean vessel and fibre diameter varying from about 40 to 60 microm and from 7.5 to 10.5 microm, respectively. Decreased water availability resulted in a reduced cell size and an important rise in vessel density, but the extent of xylem plasticity was both genotype and trait dependent. Vessel diameter and theoretical xylem-specific hydraulic conductivity correlated positively with stomatal conductance, carbon isotope discrimination and growth performance-related traits and negatively with intrinsic WUE, especially under water deficit conditions. Vessel diameter and vessel density measured under water deficit conditions correlated with the relative losses in biomass production in response to water deprivation; this resulted from the fact that a more plastic xylem structure was generally accompanied by a larger loss in biomass production.
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diversity of leaf traits related to productivity in 31 Populus deltoides x Populus nigra clones
Tree Physiology, 2005Co-Authors: Nicolas Marron, Erwin Dreyer, Francis Delmotte, Marc Villar, Didier Delay, Eric Boudouresque, Jeanmichel Petit, Jeanmarc Guehl, Franck BrignolasAbstract:To test if some leaf parameters are predictors of productivity in a range of Populus deltoides (Bartr.) Marsh. x P. nigra L. clones, we assessed leaf traits and productivity in 2-month-old rooted cuttings from 31 clones growing in 4-l pots in a greenhouse, under conditions of controlled temperature and optimal irrigation. We evaluated four groups of variables describing (1) productivity (total biomass), (2) leaf growth (total leaf number increment and total leaf area increment rate), (3) leaf structure (specific leaf area and nitrogen and carbon contents) and (4) carbon isotope discrimination (delta), which is negatively correlated with time-integrated water-use efficiency. High-yielding clones did not necessarily display high leaf growth rates, but they displayed a larger total leaf area, lower specific leaf area and lower leaf nitrogen concentration than clones with low productivity. Total leaf area was mainly controlled by maximal individual leaf area and total leaf area increment rate (r = 0.51 and 0.56, respectively). Carbon isotope discrimination did not correlate with total biomass, but it was associated with total number of leaves and total leaf area increment rate (r = 0.39 and 0.45, respectively). Therefore, leaf area and specific leaf area were better indicators of productivity than leaf growth traits. The observed independence of delta from biomass production provides opportunities for selecting poplar clones combining high productivity and high water-use efficiency.
Ramesh Murthy - One of the best experts on this subject based on the ideXlab platform.
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effect of elevated co2 concentration and vapour pressure deficit on isoprene emission from leaves of Populus deltoides during drought
Functional Plant Biology, 2004Co-Authors: Emiliano Pegoraro, Edward G Bobich, Greg A Barrongafford, Katherine Ann Grieve, Yadvinder Malhi, Ramesh MurthyAbstract:To further our understanding of the influence of global climate change on isoprene production we studied the effect of elevated [CO2] and vapour pressure deficit (VPD) on isoprene emission rates from leaves of Populus deltoides Bartr. during drought stress. Trees, grown inside three large bays with atmospheres containing 430, 800, or 1200 μmol mol-1 CO2 at the Biosphere 2 facility, were subjected to a period of drought during which VPD was manipulated, switching between low VPD (approximately 1 kPa) and high VPD (approximately 3 kPa) for several days. When trees were not water-stressed, elevated [CO2] inhibited isoprene emission and stimulated photosynthesis. Isoprene emission was less responsive to drought than photosynthesis. As water-stress increased, the inhibition of isoprene emission disappeared, probably as a result of stomatal closure and the resulting decreases in intercellular [CO2] (Ci). This assumption was supported by increased isoprene emission under high VPD. Drought and high VPD dramatically increased the proportion of assimilated carbon lost as isoprene. When measured at the same [CO2], leaves from trees grown at ambient [CO2] always had higher isoprene emission rates than the leaves of trees grown at elevated [CO2], demonstrating that CO2 inhibition is a long-term effect.
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nocturnal warming increases photosynthesis at elevated co2 partial pressure in Populus deltoides
New Phytologist, 2004Co-Authors: Matthew H Turnbull, Ramesh Murthy, David T Tissue, Xianzhong Wang, Ashley D Sparrow, Kevin L GriffinAbstract:Summary • We measured night-time respiration and daytime photosynthesis of leaves in canopies of 4 m tall cottonwood (Populus deltoides) trees to investigate the link between leaf respiration and photosynthetic capacity. • Trees were grown at three CO2 partial pressures [p(CO2)a] (42, 80, 120 Pa) and experimentally exposed to differing nocturnal temperatures (15, 20 or 25°C), but constant daytime temperatures (30–32°C), in a short-term whole-ecosystem environmental manipulation. • Rates of night-time leaf dark respiration (Rd) increased significantly at all growth CO2 partial pressures when nocturnal temperatures were increased from 15 to 25°C. Predawn leaf nonstructural carbohydrate (soluble sugars and starch) content was significantly lower at the higher night temperatures. Photosynthetic capacity (Amax) during the day increased significantly between 15 and 25°C at 42 and 80 Pa, but not at 120 Pa. • These findings indicate that the previously determined relationships between elevated night-time temperature, dark respiration and increased photosynthetic capacity may also hold at elevated p(CO2)a. This response may have a significant influence on plant and ecosystem carbon exchange under global change scenarios.
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the relative impacts of daytime and night time warming on photosynthetic capacity in Populus deltoides
Plant Cell and Environment, 2002Co-Authors: Matthew H Turnbull, Ramesh Murthy, Kevin L GriffinAbstract:In order to investigate the relative impacts of increases in day and night temperature on tree carbon relations, we measured night-time respiration and daytime photosynthesis of leaves in canopies of 4-m-tall cottonwood ( Populus deltoides Bartr. ex Marsh) trees experiencing three daytime temperatures (25, 28 or 31 ∞ C) and either (i) a constant nocturnal temperature of 20 ∞ C or (ii) increasing nocturnal temperatures (15, 20 or 25 ∞ ∞ ∞ C). In the first (day warming only) experiment, rates of night-time leaf dark respiration ( R dark ) remained constant and leaves displayed a modest increase (11%) in light-saturated photosynthetic capacity ( A max ) during the day (1000‐1300 h) over the 6 ∞ C range. In the second (dual night and day warming) experiment, R dark increased by 77% when nocturnal temperatures were
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canopy position affects the temperature response of leaf respiration in Populus deltoides
New Phytologist, 2002Co-Authors: Kevin L Griffin, Matthew H Turnbull, Ramesh MurthyAbstract:Summary • Leaf respiration and its temperature response were measured in 4-m-tall, 1-yr-old Populus deltoides trees to assess the effect of within-canopy distribution of respiratory physiology on total foliar C exchange of a model ecosystem at Biosphere 2. • Over the course of five nights, air temperature was varied over a 10°C range and the steady-state rate of leaf respiration was measured. These data were then modeled to calculate the temperature response of leaf and canopy respiration. • Results indicate that there is considerable within-canopy variation in both the rate of respiration and its temperature response and that these variables are most strongly related to leaf carbohydrate and leaf N. Scaling these results to the ecosystem level demonstrates the importance of quantifying the vertical distribution of respiratory physiology, particularly at lower temperatures. • Simplifying assumptions regarding the variation in respiration and its temperature response with canopy height tend to result in an underestimation of the actual C loss if the assumptions are based on lower- or mid-canopy leaf physiology, but overestimate C loss if the model assumptions are based on upper-canopy physiology.
Timothy J Tschaplinski - One of the best experts on this subject based on the ideXlab platform.
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the nature of the progression of drought stress drives differential metabolomic responses in Populus deltoides
Annals of Botany, 2019Co-Authors: Timothy J Tschaplinski, Lee E. Gunter, Sara S Jawdy, Paul E Abraham, Nancy L Engle, Xiaohan Yang, Madhavi Z Martin, Gerald A TuskanAbstract:Background and aims The use of woody crops for Quad-level (approx. 1 × 1018 J) energy production will require marginal agricultural lands that experience recurrent periods of water stress. Populus species have the capacity to increase dehydration tolerance by lowering osmotic potential via osmotic adjustment. The aim of this study was to investigate how the inherent genetic potential of a Populus clone to respond to drought interacts with the nature of the drought to determine the degree of biochemical response. Methods A greenhouse drought stress study was conducted on Populus deltoides 'WV94' and the resulting metabolite profiles of leaves were determined by gas chromatography-mass spectrometry following trimethylsilylation for plants subjected to cyclic mild (-0.5 MPa pre-dawn leaf water potential) drought vs. cyclic severe (-1.26 MPa) drought in contrast to well-watered controls (-0.1 MPa) after two or four drought cycles, and in contrast to plants subjected to acute drought, where plants were desiccated for up to 8 d. Key results The nature of drought (cyclic vs. acute), frequency of drought (number of cycles) and the severity of drought (mild vs. severe) all dictated the degree of osmotic adjustment and the nature of the organic solutes that accumulated. Whereas cyclic drought induced the largest responses in primary metabolism (soluble sugars, organic acids and amino acids), acute onset of prolonged drought induced the greatest osmotic adjustment and largest responses in secondary metabolism, especially populosides (hydroxycinnamic acid conjugates of salicin). Conclusions The differential adaptive metabolite responses in cyclic vs. acute drought suggest that stress acclimation occurs via primary metabolism in response to cyclic drought, whereas expanded metabolic plasticity occurs via secondary metabolism following severe, acute drought. The shift in carbon partitioning to aromatic metabolism with the production of a diverse suite of higher order salicylates lowers osmotic potential and increases the probability of post-stress recovery.
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quantitative proteome profile of water deficit stress responses in eastern cottonwood Populus deltoides leaves
PLOS ONE, 2018Co-Authors: Paul E Abraham, Lee E. Gunter, Sara S Jawdy, Benjamin J Garcia, Nancy L Engle, Xiaohan Yang, Daniel Jacobson, Robert L Hettich, Gerald A Tuskan, Timothy J TschaplinskiAbstract:Drought stress is a recurring feature of world climate and the single most important factor influencing agricultural yield worldwide. Plants display highly variable, species-specific responses to drought and these responses are multifaceted, requiring physiological and morphological changes influenced by genetic and molecular mechanisms. Moreover, the reproducibility of water deficit studies is very cumbersome, which significantly impedes research on drought tolerance, because how a plant responds is highly influenced by the timing, duration, and intensity of the water deficit. Despite progress in the identification of drought-related mechanisms in many plants, the molecular basis of drought resistance remains to be fully understood in trees, particularly in poplar species because their wide geographic distribution results in varying tolerances to drought. Herein, we aimed to better understand this complex phenomenon in eastern cottonwood (Populus deltoides) by performing a detailed contrast of the proteome changes between two different water deficit experiments to identify functional intersections and divergences in proteome responses. We investigated plants subjected to cyclic water deficit and compared these responses to plants subjected to prolonged acute water deficit. In total, we identified 108,012 peptide sequences across both experiments that provided insight into the quantitative state of 22,737 Populus gene models and 8,199 functional protein groups in response to drought. Together, these datasets provide the most comprehensive insight into proteome drought responses in poplar to date and a direct proteome comparison between short period dehydration shock and cyclic, post-drought re-watering. Overall, this investigation provides novel insights into drought avoidance mechanisms that are distinct from progressive drought stress. Additionally, we identified proteins that have been associated as drought-relevant in previous studies. Importantly, we highlight the RD26 transcription factor as a gene regulated at both the transcript and protein level, regardless of species and drought condition, and, thus, represents a key, universal drought marker for Populus species.
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Agronomic performance of Populus deltoides trees engineered for biofuel production
Biotechnology for Biofuels, 2017Co-Authors: David Macaya-sanz, Jin‐gui Chen, Sandra J. Simon, Anthony C. Bryan, Udaya C. Kalluri, Agni Kumar Biswal, Wellington Muchero, Lee E. Gunter, Timothy J Tschaplinski, Raja PayyavulaAbstract:BackgroundOne of the major barriers to the development of lignocellulosic feedstocks is the recalcitrance of plant cell walls to deconstruction and saccharification. Recalcitrance can be reduced by targeting genes involved in cell wall biosynthesis, but this can have unintended consequences that compromise the agronomic performance of the trees under field conditions. Here we report the results of a field trial of fourteen distinct transgenic Populus deltoides lines that had previously demonstrated reduced recalcitrance without yield penalties under greenhouse conditions.ResultsSurvival and productivity of the trial were excellent in the first year, and there was little evidence for reduced performance of the transgenic lines with modified target gene expression. Surprisingly, the most striking phenotypic effects in this trial were for two empty-vector control lines that had modified bud set and bud flush. This is most likely due to somaclonal variation or insertional mutagenesis. Traits related to yield, crown architecture, herbivory, pathogen response, and frost damage showed few significant differences between target gene transgenics and empty vector controls. However, there were a few interesting exceptions. Lines overexpressing the DUF231 gene, a putative O-acetyltransferase, showed early bud flush and marginally increased height growth. Lines overexpressing the DUF266 gene, a putative glycosyltransferase, had significantly decreased stem internode length and slightly higher volume index. Finally, lines overexpressing the PFD2 gene, a putative member of the prefoldin complex, had a slightly reduced volume index.ConclusionsThis field trial demonstrates that these cell wall modifications, which decreased cell wall recalcitrance under laboratory conditions, did not seriously compromise first-year performance in the field, despite substantial challenges, including an outbreak of a stem boring insect (Gypsonoma haimbachiana), attack by a leaf rust pathogen (Melampsora spp.), and a late frost event. This bodes well for the potential utility of these lines as advanced biofuels feedstocks.
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agronomic performance of Populus deltoides trees engineered for biofuel production
Biotechnology for Biofuels, 2017Co-Authors: David Macayasanz, Sandra J. Simon, Anthony C. Bryan, Udaya C. Kalluri, Agni Kumar Biswal, Wellington Muchero, Lee E. Gunter, Timothy J Tschaplinski, Jingui Chen, Raja PayyavulaAbstract:One of the major barriers to the development of lignocellulosic feedstocks is the recalcitrance of plant cell walls to deconstruction and saccharification. Recalcitrance can be reduced by targeting genes involved in cell wall biosynthesis, but this can have unintended consequences that compromise the agronomic performance of the trees under field conditions. Here we report the results of a field trial of fourteen distinct transgenic Populus deltoides lines that had previously demonstrated reduced recalcitrance without yield penalties under greenhouse conditions. Survival and productivity of the trial were excellent in the first year, and there was little evidence for reduced performance of the transgenic lines with modified target gene expression. Surprisingly, the most striking phenotypic effects in this trial were for two empty-vector control lines that had modified bud set and bud flush. This is most likely due to somaclonal variation or insertional mutagenesis. Traits related to yield, crown architecture, herbivory, pathogen response, and frost damage showed few significant differences between target gene transgenics and empty vector controls. However, there were a few interesting exceptions. Lines overexpressing the DUF231 gene, a putative O-acetyltransferase, showed early bud flush and marginally increased height growth. Lines overexpressing the DUF266 gene, a putative glycosyltransferase, had significantly decreased stem internode length and slightly higher volume index. Finally, lines overexpressing the PFD2 gene, a putative member of the prefoldin complex, had a slightly reduced volume index. This field trial demonstrates that these cell wall modifications, which decreased cell wall recalcitrance under laboratory conditions, did not seriously compromise first-year performance in the field, despite substantial challenges, including an outbreak of a stem boring insect (Gypsonoma haimbachiana), attack by a leaf rust pathogen (Melampsora spp.), and a late frost event. This bodes well for the potential utility of these lines as advanced biofuels feedstocks.